The use of inorganic fillers to improve certain properties of products is known in the art. For example inert inorganic fillers such as clay, talc, asbestos fibers, silica, barium sulfate and calcium carbonate have been used with polyolefins in caulking and sealing compounds. The use of these inert inorganic fillers has also been taught to be useful for increasing the dielectric strength of non-elastomeric thermoplastic materials.
The use of polyolefins in forming sheet material is also known. Thermoplastic material which has been extruded into sheets has been found suitable for subsequent thermoforming into various types of products such as containers. The use of thermoplastic materials in forming such products has been found to be desirable from a manufacturing and expense perspective. Known materials, however, suffer from the problem of sagging when they are thermoformed as wide sheets. Furthermore, some known materials have lacked consumer appeal due to their appearance such as having a low gloss when formed into final products.
It would, therefore, be desirable to provide a thermoplastic sheet capable of thermoforming into end products such as containers, cups, trays, and the like, having an increased resistance to sagging while providing a finished surface having an attractive high gloss. The reduction of sheet sag allows for better process control and for wider sheets to be used which means more parts/min. and improved manufacturing economics.